Blower Motor Inoperative at Any Speed (Front)

Circuit Description

The airflow is controlled by modulating the commanded blower voltage that varies the blower speed. Under automatic control, the blower adjustments are made based upon the following factors:

• / The vehicle speed
• / The coolant temperature
• / The sun load sensor

Special cases exist that may override the normal operation of the blower in order to limit the following conditions:

• / Snow ingestion
• / Purging the air ducts
• / Cooling the instrument panel cluster
• / Enhancing the heater warm-up performance

Test Description

If the blower is inoperative in the normal operating procedure, but operates properly in override, the IPC or the data line between the IPC and the heater and A/C programmer are suspect.

Step / Action / Value(s) / Yes / No
1 / Did you perform the Diagnostic System Check? / -- / Go to Step2 / Go to Diagnostic System Check
2 /
  1. Turn the key to the ON position.
  2. With the engine running, connect the Scan Tool .
  3. Set the blower on high (99%).
  4. Use the Scan Tool in order to display HVAC DATA, BLOWER MOTOR %.
  5. Change the blower speed. Observe the change in speed as the numbers decrease.
Did you complete the procedure? / -- / Go to Step3 / --
3 / Is the blower non-operational or intermittent? / -- / Go to Step6 / Go to Step4
4 / Does the blower speed consistently decrease at a gradual rate from 99 to approximately30, and then stop? / -- / Go to Step7 / Go to Step5
5 / Is the blower speed consistent, then OFF? / -- / Go to Step8 / --
6 /
  1. Use a Scan Tool in order to view the blower speed.
  2. Command the blower to the HI speed (100%) using CCP.
  3. Command the blower to the LO speed (42%).
Does the commanded value equal the displayed value on the Scan Tool ? / -- / Go to Step10 / Go to Step9
7 / The blower is operating properly.
Inspect for improper temperature control.
Did you inspect for improper temperature control? / -- / Go to Step18 / --
8 /
  1. Exit the diagnostic.
  2. Start the engine.
  3. Select the LO blower.
  4. Measure the voltage at blower connectorB.
Is the voltage greater than the specified value? / 9V / Go to Step17 / Go to Step13
9 /
  1. Use the Scan Tool in order to view the blower speed.
  2. Set the A/C system to 75° AUTO.
  3. Increase or decrease the set temperature.
Is the blower speed (%) within the specified value? / 40-100% / Go to Step10 / Go to Step11
10 / Measure the voltage at the blower motor connectorB.
Is the voltage less than the specified value? / 4V / Go to Step13 / Go to Step12
11 / Replace the heater and A/C programmer. Refer to Programmer Replacement .
Is the repair complete? / -- / Go to Step18 / --
12 /
  1. Disconnect the blower.
  2. Inspect the resistance of connectorC to the battery voltage.
  3. Inspect the resistance of connectorA to ground.
Is the resistance greater than the specified value? / 1.0ohms / Go to Step14 / Go to Step15
13 /
  1. Inspect CKT754.
  2. If CKT754 is OK, replace the heater and A/C programmer. Refer to Programmer Replacement .
Did you complete the repair? / -- / Go to Step18 / --
14 /
  1. Inspect the fuse.
  2. Repair CKT542 as required. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair? / -- / Go to Step18 / --
15 /
  1. Turn the key OFF.
  2. Measure the resistance between connectorA and ground.
Is the resistance less than the specified value? / 50ohms / Go to Step19 / Go to Step20
16 / Replace the blower motor assembly. Refer to Blower Motor and Fan Replacement .
Did you complete the repair? / -- / Go to Step18 / --
17 / Set the blower speed to HI.
Does the voltage change to less than the specified value? / 4V / Go to Step16 / Go to Step13
18 /
  1. Use the Scan Tool in order to clear the DTCs.
  2. Verify proper operation of the system.
Did you clear the DTCs and verify the operation? / -- / Go to Diagnostic System Check / --
19 / Inspect CKT50 for an open. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair? / -- / Go to Diagnostic System Check / --
20 /
  1. Turn the key off.
  2. Measure the resistance between connectorB and ground.
Is the resistance less than the specified value? / 250Kohms / Go to Step13 / Go to Step16

Programmer Replacement

Removal Procedure

Caution:Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

  1. Disconnect the negative battery cable.
  2. Remove the right sound insulator. Refer to Closeout/Insulator Panel Replacement - Right in Instrument Panel, Gauges and Console.
  3. Remove the instrument panel compartment. Refer to Storage Compartment Replacement - Instrument Panel (I/P) in Instrument Panel, Gauges and Console.

  4. Disconnect the vacuum and electrical connectors from the programmer(1).

  5. Remove the programmer(1) from the vehicle.
Installation Procedure


  1. Install the programmer(1) to the vehicle.

  2. Connect the vacuum and electrical connectors to the programmer(1).
  3. Install the right sound insulator. Refer to Closeout/Insulator Panel Replacement - Right in Instrument Panel, Gauges and Console.
  4. Install the instrument panel compartment. Refer to Storage Compartment Replacement - Instrument Panel (I/P) in Instrument Panel, Gauges and Console.
  5. Connect the negative battery cable.